1. Field of the Invention
The present invention relates to switch devices that are operated with a tilting movement by using, for example, an operating knob. In particular, the present invention relates to a switch device that tilts a conductive plate to move into and out of contact with stationary contacts to switch between ON and OFF modes. Such switch device are used as a driving switch for an automatic window unit in a vehicle.
2. Description of the Related Art
FIG. 9 is a sectional view of a conventional switch device. As is shown in FIG. 9, a case 1 includes a bottom wall 1a on which a first stationary contact 2a, a second stationary contact 2b, and a third stationary contact 2c are fixed by insert molding; and three terminals 8 which extend from the stationary contacts 2a, 2b, and 2c and protrude downward from the case 1. The stationary contacts 2a, 2b, and 2c are exposed on the bottom wall 1a, the stationary contact 2a being disposed in the center to function as a fulcrum for tilting a conductive plate 3. The conductive plate 3 is a metal plate with an M-shape from a side view, having a depressed portion 3a between two elevated portions 3b and 3c. One longitudinal end of the conductive plate 3 can move into and out of contact with the stationary contact 2b, while the other end has the same movement with the stationary contact 2c. An actuating portion 4a of a driver 4 is disposed on the conductive plate 3. A coil spring 5 causes the driver 4 to constantly apply force towards the bottom wall 1a, whereby the actuating portion 4a is in resilient contact with the conductive plate 3. The driver 4 and the coil spring 5 are mounted inside a housing 6a of a tilt lever 6. The tilt lever 6 is tiltably supported by a cover 7 which covers the case 1. An operating knob, which is not shown in FIG. 9, is attached to the tilt lever 6 by an appropriate method. An operator of the apparatus tilts the operating knob to move the tilt lever 6, thereby sliding the actuating portion 4a on the conductive plate 3.
FIG. 9 shows a neutral state (stand-by mode) where the tilt lever 6 is not being moved. In FIG. 9, the stationary contacts 2a and 2c are connected via the conductive plate 3, and the stationary contacts 2a and 2b are kept in an OFF mode. When the operating knob is pressed to tilt the lever 6 clockwise with respect to the drawing, the actuating portion 4a slides on the elevated portion 3b of the conductive plate 3 as the coil spring 5 becomes compressed. As the actuating portion 4a passes over the stationary contact 2a, the conductive plate 3 tilts counter-clockwise. As a result, the conductive plate 3 moves out of contact with the stationary contact 2c and moves into contact with the stationary contact 2b to create a state such that the stationary contacts 2a and 2b are connected via the conductive plate 3 to be switched to an ON mode. When the force applied from the operating knob is removed, the restoring force of the coil spring 5 causes the actuating portion 4a on the elevated portion 3b to slide in the opposite direction. This causes the actuating portion 4a to reversely pass over the stationary contact 2a to tilt the conductive plate 3 clockwise, whereby the switch device is switched back to the stand-by mode shown in FIG. 9. Consequently, the stationary contacts 2a and 2b are automatically switched back to an OFF mode.
If the tilt lever 6 is tilted counterclockwise in a stand-by mode shown in FIG. 9, the actuating portion 4a slides along the elevated portion 3c. However, since the conductive plate 3 is already pressed against the stationary contact 2c and therefore cannot be tilted, the stationary contacts 2a and 2b are kept disconnected to be in an OFF mode.
The switch devices of this type are extensively used as a driving switch for automatic window units in vehicles. In such a unit, a driving signal for opening and closing the window is output for the period of time that an operating knob is pressed, by which the window can be manually operated until the desired opening is obtained.
The above-mentioned conventional switch device has the driver 4 combined with the coil spring 5 on the conductive plate 3 and therefore requires a large housing 6a in the tilt lever 6. For this reason, the tilt lever 6 requires a reasonable height and may interfere with the achievement of a lower profile of the apparatus. Furthermore, the tilting movement requires a clearance space C between the tilt lever 6 and the cover 7. Through this space, foreign particles, such as dust, may enter and land on the contacts in the case 1, which may lead to a loss of reliability in the connections.
In a driving switch of an automatic window unit in a vehicle, two groups of the stationary contacts 2a, 2b, and 2c are disposed on the bottom wall 1a of the case 1 in a pair of rows, each group being provided with components such as the conductive plate 3 and the actuating portion 4a to form first and second switch elements. When the operating knob is pressed in one direction, the first switch element outputs a driving signal for opening, whereas pressing the knob in the other direction turns on the second switch element to output a driving signal for closing. To achieve such a double-pole double-throw switch device with the structure of the conventional apparatus as is shown in FIG. 9, the tilt lever 6 must be assembled with the case 1 and the cover 7 very carefully without misaligning the driver 4 and the coil spring 5. Such assembly process is extremely inefficient.
Also, in a driving switch of an automatic window unit in a vehicle, a function which enables the window to be fully opened or fully closed through one-touch operation is in demand, although adding this type of function to the conventional switch device would normally require a push switch in the vicinity of the case 1. In such a unit, when the tilt lever 6 is tilted with an operating knob, a single-purpose driving element presses the push switch to output a driving signal for a full-opening or a full-closing operation. However, if the driving element for the push switch is disposed outside the case 1 in a preferable position where the element can operate with respect to the timing of the movement of the driver 4, the whole apparatus may lead to a large-scale and a complex structure.
An object of the present invention is to solve the problems of the conventional switch devices and to provide a highly reliable switch device having a lower profile and more simple structure and being capable of ready assembly.
The switch device of the present invention includes a case with a bottom wall and a top opening; two switch elements assembled in the case; a common leaf spring whose restoring force is applied to the two switch elements; and a cover that presses a leaf spring and that covers the top opening. Each of the switch element includes stationary contacts that are fixed to the bottom wall of the case; a conductive plate that is disposed on the bottom wall and is tiltable to move into and out of contact with the stationary contacts; and a driver disposed on the conductive plate, the driver being rotatable around a shaft thereof and movable vertically. The driver includes a protruding receiver which protrudes from the case; and a sliding portion that slides on a slope of the conductive plate when the protruding receiver is pressed downward. The leaf spring includes a compressed portion which is resiliently compressed by the cover; and a pair of pressing strips which connect with the compressed portion and resiliently urge the shaft of the driver towards the bottom wall of the case.
With the pressing strip resiliently urging the shaft of the driver, the force applied by an operating knob to the protruding receiver moves the driver and causes the sliding portion to slide on the slope of the conductive plate. This allows the conductive plate to tilt and therefore excludes the need for an external driving element for tilting the conductive plate to move into and out of contact with the stationary contacts. Furthermore, the leaf spring can be disposed in the narrow space provided on the shafts of the drivers, whereby an apparatus with a lower profile can be readily achieved. The protruding receiver, which protrudes from the case, can turn on the push switch in the vicinity of the case when the operating knob is pressed with a great force to achieve a multifunctional apparatus. The additional driving element for the push switch therefore is not necessary, leading to a low-profile apparatus with a more simple, compact structure. After the conductive plates and the drivers include in the two switch elements are disposed onto the bottom wall, the leaf spring and the cover are disposed onto the switch elements, whereby the one common leaf spring applies a restoring force to both of the switch elements. This enables an automatic assembly of the apparatus. Furthermore, because the top opening of the case is covered with the cover, the case is protected from foreign dust particles, maintaining reliability in the connections for a longer period of time.
In this structure, the compressed portion of the leaf spring includes first bent strips formed of sharply bent first longitudinal end segments extending from the pressing strips, the first longitudinal end segments being bridged; and a second bent strip formed of sharply bent second longitudinal end segments extending from the pressing strips, the second longitudinal end segments being bridged. The cover is mounted above the leaf spring disposed at the top of the case and resiliently urges the first and the second bent strips. Thus, a resilient force is applied towards the pressing strips to create a spring force therein. The leaf spring, which applies its restoring force to the switch elements, has a simple, low-profile structure and contributes to lower costs of the parts as well as a lower profile apparatus.
The structure includes sidewalls orthogonal to the bottom wall for determining the longitudinal position of the pressing strips, and guides in the shafts of the drivers for determining the lateral position. Thus, the positioning of the leaf spring at the top of the case can be performed during the assembly, as well as preventing the misalignments of the components. Accordingly, the automatic assembly becomes easier and greatly reduces the assembly costs.
In plan view, this structure may preferably have the two switch elements including the stationary contacts, the conductive plate, and the driver being disposed point-symmetrically so that the apparatus may have a smaller size.
The present invention discloses a switch device which is driven when an operating knob is directly pressed against drivers, the drivers then being generated a tilting movement to tilt conductive plates so that the apparatus can be turned on. Since a leaf spring is disposed in narrow spaces provided on shafts of the drivers, an apparatus with a low profile can be readily achieved. Furthermore, in the assembly of this switch device, the conductive plates and the drivers composing the two switch elements are mounted on a bottom wall of a case, and the leaf spring and a cover are then mounted on the switch elements, whereby both of the switch elements receive the restoring force of one common leaf spring. Thus, a highly efficient, automatic assembly of the apparatus can be achieved. Furthermore, because a top opening of the case is covered with the cover, the case is protected from foreign dust particles to maintain reliability in the connections for a longer period of time.